Means for securing tubes to headers



April 5, 1932- w. H. ARMACOST ET AL 1,852,279

IEANS FOR SECURING TUBES TO HEADERS Filed May 16, 1929 2 Sheets-Sheet l2 5 vvv'T I /5 I I a 2 3 5 Fig 5 I 6 ATTORNEY.

April 5, 1932.

W. H. ARMACO Filed May 16 ST ET AL 1,852,279

IEANS FOR SECURING TUBES TO HEADERS 1929 2 Sheets-Sheet 2 r p P P ATTORNE Y.

Patented Apr. 5, 1932 UNITED STATES PATENT OFFICE WILBUB H. ARMAGOST, OFNEW YORK, AND JOHN K. SPIRSON, OF BROOKLYN, NEW

YORK, ASSIGNORS TO THE SUPERHEATER COMPANY, OF NEW YORK, N. Y.

MEANS FOR SECURING TUBES TO HEADERS Application filed May 16,

The present invention relates to means for securing tubes to headers orthe like and has particular reference to structures such as steamsuperheaters or the like in which a numher of tubular elements conveyingfluid under pressure are detachably secured at their ends todistributing or collecting headers.

Heretofore tubular elements of this character have been detachablyconnected to headm are through the medium of releasable clampsociatedtherewith.

The use of much higher steam pressures in structures of this nature hasrendered the forms of joints heretofore employed unsatisfactory, due tothe distortion occuring in the header and joint structure because of theeX- treme pressure employed, such distortion causing difficulty inmaintaining pressure tight joints.

The principal purpose of the present i11- vention is the provision of animproved form of structure by means of which the above ditliculty may beeliminated and also by means of which the advantages of a detachableconnection between header and tubes may be retained while at the sametime employing a lighter header than would otherwise be possible.

The manner in which the purpose of the invention is carried into effectmay best be understood from a consideration of the ensuing descriptionof the embodiments thereof shown in the accompanying drawings in whichFig. 1 is a fragmentary elevation, partly in section, of a header andtube assembly embodying the invent-ion; Fig. 2 is a fragmentary sectiontaken on the line 2-2 of llig. 1 Fig. 3 is a view similar to Fig. 1showing another form of the invention; Fig. 4 is a section taken on theline -l4 of Fig. 3, and Figs. 5 and 6 are views similar to Fig. 1showing still other forms of the invention. Referring now to Figs. 1 and2, the header is shown at 1 and while for purposes of illustration acylindrical header has been shown, it will be readily apparent as thedescription 1929. Serial No. 363,676.

proceeds that the invention is equally Well applicable to headers'havingother cross sectional forms.

The header wall. is suitably perforated to receive a member ofrelatively short nipples 2 placed in suitably spaced relation and permanently secured to the header. As shown in the figures, the nipples 2are threaded through the header wall and sealed against leakage bymeansof the Welds 3. methods of securing the nipples, may obviously beemployed.

The outer ends of the nipples are upset to form shouldered heads 4 andinternal conical seats 5 are provided in these heads. A bar 6 havingsuitably spaced counter-bored apertures 7 therethrough is fitted overeach pair of nipples so that the upset heads 4 of the nipples lie Withinthe counter-bored portions of the apertures 7 The main portions of thebores of the latter are preferably slightly larger in diameter than thenormal diameter of the nipples 2. Between the apertures, through whichthe nipples pass, the clamp ing bolt 8 is secured to bar 6. In the formillustrated the bolt 8 is in the form of a stud threaded through acentrally located threaded hole 9 in bar 6, and the upper end of thebolt is threaded as at 10 for a purpose to be described later.Equivalent means of securing a clamping bolt to bar 6 may be employed.The tubular elements'll are each formed with an enlarged head 12, saidheads being formed with two external spherically contoured seats 13 and14, these surfaces being struck from a common center. A washer 15 havinga bore slightly larger than the external diameter of the tubular element11 is placed around each of the elements, said washer being countersunkat 16 to provide a conical bearing surface adapted to contact with thespherical surface 14 of the element head 12. A yoke 17 having a centralbore 18 slightly larger than bolt 8 is fitted over the extended end ofthe latter, said yoke being bifurcated at its ends to form bearingsurfaces or feet 19 acting on opposite sides of each of a pair ofwashers 15. The upper end of bore 18 is countersunk as at 20 to providea conical bearing surface against which the Other spherical surface ofwasher 21 bears. The latter has a plane upper surface engaged by the nut22 screwed on the threaded end 10 of the clamp bolt.

In assembling the structure above described,'nipples 2 are firstinserted; through the apertures in bar 6 and are then screwed and weldedin place in the header wall 1. Stud 8 may be assembled either before orafter the nipples are secured in the header. lVashers 15 are slippedover the ends of the tubular elements 11 before the upset heads of thelatter are formed, unless the opposite ends of these elements aresecured by means of a joint which does not require enlargement of theexternal diameter of the elements. The elements are then placed with theseats 13 engaging seats 5 of the nipples; the yoke 17 is placed inposition and the elements drawn into fluid pressure tight engagementwith the nipples by means of the nut 22.

As will be obvious, a line contact will re sult between surfaces 18 and5 and also be-- tween surfaces 1a and 16 and because of the commoncenter from which surfaces 13 and 14 are generated, it willbe apparentthat a certain degree of universal motion is possible for the elements11 without in any way affecting the joint between 'the'elements and thenipples. Also because of this form of construction the yoke 17 canadjust itself to slight inequalities such as variation in the thicknessof washers 15, so that the pressure exerted thereby is evenlydistributed to the two element heads held by the yoke.

Turning now to Figs. 3 and at; another form of joint is shown in whichthe nipples 2-a are" expanded into the header wall 1a to form apermanent joint which may also be further sealed by means of thecircumferential welds 3-a. The bar 6-0, instead of being counter-boredas in the form shown in Fig. 1 is countersunk, and enlarged heads t-a ofthe nipples are formed by expanding the walls of the nipples against theconical seats formed by countersinking the apertures 7a in the bar. Thisexpanding of the nipples is preferably accomplished by a rolling processwhich obviously will tend to force the bar 6-a toward the wall of theheader. A number of lugs or feet 23 are preferably provided on the underside of bar 6-60 to form a support for the latter so that the majorportion of the bar is spaced a short distance from the header for apurpose which will appear later. As in the form previously described,the clamp bolt 8 is in the form of a stud centrally located in the bar6-a, and the heads 12 of the elements 11 are secured to the nipples 2ain the same manner as that previously described by means of washers 15,yoke 17 and nut 22.

In Fig. 5, another form of joint is shown in which the enlarged heads 4bof nipples 2b are formed with external spherical bearing surfaces 2 1which engage the conical surfaces 25 formed by countersinking theapertures 7-6 in the bar 6-6. In this connection it is to be noted thata clearance is provided between the nipples 2-b and the apertures 7b toallow the bar- 6b to align itself. The remainder of the clamping meansis the same as that already described.

In the form shown in Fig. 6 the enlarged outer ends or heads 40 ofnipples 20 are formed in the same manner as the heads 12 of the elements11, that is, with two spherical seats 26 and 27 struck from a commoncenter. 1 The surfaces 26 engage conical bearing surfaces formed bycountersinking the apertures 70 in bar 6c, this construction beingsimilar to that shown in Fig. 5. Instead, however, of having the elementheads 12 seated directly against the nipples, an intermediate bar 28 isprovided having suitably spaced bores therethrough, each of said boresbeing countersunk at both ends to form conical bearing surfaces againstwhich the hearing surfaces 27 of the nipples 2c and 13 of the elementheads 12 seat. Bar 28 is also provided with a central bore 29 throughwhich the clamp bolt 8 passes and the usual washers 15, clamp 17 and nut22 are employed to draw the heads -c and 12 into pressure tightengagement with their respective seats in the bar 28.

In the several forms hereinbefore described, it will be apparent thatthe joints provided between the nipples and the elements will not besubject to distortion such as would bethe case if the seats againstwhich the element heads bear were formed in the wall of the header or anelement integrally connected therewith.

In order to maintain pressure tight joints of the character hereinbeforedescribed it is necessary from time to time to regrind the bearingsurfaces, and where such surfaces form a portion of the header the seatsmay be reground only a limited number of times before the removal ofmetal by the regrinding process causes undesirable weakening of theheader wall. By means of the present invention the permissible number ofregrindings of the seats is substantially unlimited, as the nippleswhich may have been reduced in thickness to an undesirable degree byregrinding operations may be readily replaced at small expense by newones. As will be readily apparent, it is a relatively simple matter tocut worn out nipples from the header and re-thread or re-expand newnipples in place, sealing them by means of new welds. In this connectionit is to be noted that because of the relatively short length of thenipples provided, they may be readily expanded into the header wall bymeans of an expander operating through the open ends of the nipples sothat hand hole plates in the header opposite the nipples are notrequired.

It is for the purpose of facilitating renewals of nipples that the feet23 are provided 011 the bar 6a, shown in Fig. 3, these feet giving aclearance between the header and the bar which permits the sealing ofreplacement nipples in the header by means of new welds Zi-a.

Obviously the arrangement of the elements 11 with respect to the headeror headers is subject to wide variation as are also the details ofconstruction of the oints, and the invention is therefore not to beconsidered as limited to the illustrative forms herein disclosed, but isto be considered as embracing all such changes and modifications as mayfall within the scope of the appended claims.

We claim:

1. Apparatus of the class described, comprising a header wall, a pair ofspaced nipples permanently secured in said wall, the outer end of eachnipple being enlarged and having an annular seat formed thereon, a pairof tubular elements each formed with an enlarged head having an annularseat thereon, and releasable clamping means for holding each of saidnipples in fluid pressure tight communication with one of said elements,said means comprising a bar acting under the enlarged heads of thenipples, an apertured yoke acting over the element head, a bolt engagingsaid bar between said nipples and extending through the aperture in saidyoke, and a nut 011 the extended end of the bolt for drawing said yokeand bar together.

2. Apparatus of the class described comprising a header wall, a pair ofspaced nipples permanently secured in said wall the outer end of eachnipple being enlarged and having an annular seat formed thereon, a pairof tubular elements each formed with an enlarged head having an annularseat thereon engaging one of said first named seats, and releasableclamping means engaging the enlarged ends of the nipples and the headsof the elements to hold the nipples and elements in pressure tightengagement.

3. Apparatus of the class described, comprising the combination of aheader wall, a pair of spaced nipples permanently secured in said wall,the outer end of each nipple being enlarged and having an internalconical seat formed thereon, a pair of tubular elements each formed withan enlarged head having an external spherical seat thereon engaging oneof said conical seats, and releasable clamping means engaging theenlarged ends of the nipples and the heads of the ele ments to hold thenipples and elements in pressure tight engagement.

at. Apparatus of the class described, comprising the combination of aheader wall, a pair of spaced nipples permanently secured in said wall,a bar having counterbored apertures therethrough through which saidnipples pass, the outer ends of said nipples betures therethroughthrough which said nipples loosely pass, the outer ends of said nipplesbeing enlarged to form heads having internal conical seats and externalspherical surfaces engaging the countersunk portions of said apertures,a bolt engaging said bar between said apertures, a pair of tubular elements each formed with an enlarged head having an external sphericalseat engaging one of said conical seats, and means engaging said studand said element heads for holding the latter in pressure tightengagement with the nipples.

WILBUR H. ARMACOST. JOHN K. SPIRSON.

